What Do You Need to Make an Offer on a House? In real estate, all offers must be in writing and are a traditional approach in contract law used to determine whether an agreement exists between two parties.I want to write a letter that is compelling. My realtor says he's not allowed to attach letters to offers because he can lose his license. Focus on three things: State your intentions, show that you have the financial means to make the purchase and make a personal appeal to the seller. The written offer is legally binding, so in most cases a simple letter won't work. Want to Stand Out From The Competition? Today we are going to talk about how to fill out a trek one to four offer. Make your opener as personal as possible. Work with your agent to submit a written offer based on local market value, specifying how and when the steps in the purchase will happen.